Effect of Chromated Copper Arsenate impregnation treatment on flexural and shear properties of Glue Laminated Eucalyptus grandis

Abstract

This study examined the effect of Chromated Copper Arsenate (CCA) preservative treatment on selected mechanical properties of glue laminated Eucalyptus grandis wood. Test specimens were prepared and tested for Modulus of Elasticity [MOE], Modulus of Rupture [MOR] and shear strength using a Universal Testing Machine in accordance with ASTM D198 and BS373. The soaking delamination test was used to test for delamination percentage. The data was analyzed using the Levene’s test for the flexural properties (MOE and MOR) and one-way ANOVA test for the shear properties at 95% significance level. The results showed that MOE and MOR decreased in the treated glulam samples by 19.1% and 13.3% respectively. The shear strength properties also decreased in the treated samples by 3.3%. However, no delamination was found in all glulams. The treated wood glulams had lower MOE, MOR and shear strength properties than that of the untreated glulams but no significant differences in strength properties were detected. In conclusion, treatment of the eucalyptus glulam with CCA does not significantly weaken its flexural and shear properties. It is recommended that glulams extracted from CCA treated Eucalyptus grandis should not be used for high structural purposes but could be used in light construction works.